Andi Kleen wrote:> Extensive discussion by various experts on the discuss@x86-64.org> mailing list concluded that the correct vector to restart an 286+ > CPU is f000:fff0, not ffff:0000. Both seem to work on current systems, > but the first is correct.

You are right. That's what a 286 does when the RESET signal is asserted.

Which is amazing, because I wrote that ffff:0000 and I was readingfrom the Phoenix BIOS book at the time. It was long ago but I'mfairly sure I got that address from the book.I just did some Googling and found that there examples of DOS codefragments using both vectors. Also, the original IBM BIOS (as theysay) had a long jump at the vector, which is presumably one of themany de facto ABIs which real mode programmers grew to depend on.